Definitions
- Virus
- Macro Virus
- Trojan/Trojan Horse
- Worm
- Virus Hoaxes
- Scams
Virus
A program or piece of code that is loaded onto your computer without your knowledge and runs against your wishes. Viruses can also replicate themselves. All computer viruses are manmade. A simple virus that can make a copy of itself over and over again is relatively easy to produce. Even such a simple virus is dangerous because it will quickly use all available memory and bring the system to a halt. An even more dangerous type of virus is one capable of transmitting itself across networks and bypassing security systems.
Since 1987, when a virus infected ARPANET, a large network used by the Defense Department and many universities, many antivirus programs have become available. These programs periodically check your computer system for the best-known types of viruses.
Some people distinguish between general viruses and worms. A worm is a special type of virus that can replicate itself and use memory, but cannot attach itself to other programs.
Macro Virus
A type of computer virus that is encoded as a macro embedded in a document. Many applications, such as Microsoft Word and Excel, support powerful macro languages. These applications allow you to embed a macro in a document, and have the macro execute each time the document is opened.
According to some estimates, 75% of all viruses today are macro viruses. Once a macro virus gets onto your machine, it can embed itself in all future documents you create with the application. Antivirus programs can protect your system against most macro viruses, although new ones are always being created that slip by the antivirus filters.
Trojan Horse
A destructive program that masquerades as a benign application. Unlike viruses, Trojan horses do not replicate themselves but they can be just as destructive. One of the most insidious types of Trojan horse is a program that claims to rid your computer of viruses but instead introduces viruses onto your computer.
The term comes from a story in Homer's Iliad, in which the Greeks give a giant wooden horse to their foes, the Trojans, ostensibly as a peace offering. But after the Trojans drag the horse inside their city walls, Greek soldiers sneak out of the horse's hollow belly and open the city gates, allowing their compatriots to pour in and capture
Worm
A program or algorithm that replicates itself over a computer network and usually performs malicious actions, such as using up the computer's resources and possibly shutting the system down.
Virus Hoaxes
Virus Hoaxes are not technically viruses, but are usually deliberate or unintentional email messages, warning people about a new virus, file or piece of software, which is supposedly harmful to their machine. Some hoaxes cause as just as much trouble as a virus by causing massive amounts of unnecessary e-mail, or advising users to delete a system file which is vital to the operation of their machine.
Most hoaxes contain warnings about alleged new viruses and their damaging consequences, demanding the reader forward the warning to as many people as possible or bogus comments from officials: FBI, software companies, news agencies, etc.
In almost all cases, these hoaxes urge you to forward the warning to all your friends and colleagues. They will mention company names such as IBM, Microsoft or AOL to give them an air of authority. Sending a warning on to a large number of contacts not only perpetuates the misinformation but also increases the load on computer networks and email servers. If you receive an e-mail message about a virus, check with a reputable source to ensure the warning is real. Sometimes hoaxes start out as viruses and some viruses start as hoaxes, so both viruses and virus hoaxes should be considered a threat.
Scams
Scams are designed to gain access to credit card and online banking details or to get you to send money. Common scams include the ANZ, Commonwealth Bank and Westpac bank scams; which arrive as an email sporting an authentic look using the same style and logo as the backs webpage. These emails direct you to a web address where you will be requested to enter details for online banking. Another example is the “Nigerian” bank scam that requests a small startup fund be sent with the potential for you to earn millions of dollars. There are also a large number of email-based pyramid schemes, which are illegal in many countries.
